SAM 19 CONFERENCES: eVTOL. State of the Art and Advances

SAM 19 CONFERENCES: eVTOL. State of the Art and Advances

Guillermo Villabrille Prades, Director of Prades I+D. He spoke about eVTOL at the SAM 19 conference. This presentation is part of the Sustainable Air Mobility conferences that took place in Madrid on June 12, 2019 at the 1st Sustainable Air Mobility Conferences held in Spain. The objective of these conferences is to bring the entire value chain of sustainable mobility into contact, not only the air, but also the land, and the infrastructure and superstructure necessary for its development, comprising a whole series of physical and cyber-physical structures , facilities and devices in which it can develop.


This conference deals with the state of the art (or technique) in which the aircraft of the Sustainable Air Mobility sector are located, showing what are the shortcomings in terms of safety, legislation, calculation and development, and then explain the proposals and alternatives that from my company Prades R&D, and my Start Up Gyrobike, can be offered, with the development of aircraft, navigation systems and mathematical theories to perfect the existing systems not only in this field, but in other much closer sectors to Civil Engineering.


We are in a moment of history in which, if we compare with the time of geographical discoveries, we will see many similarities, since these were made possible by:


  • Advances in security and ships that allowed for increasingly distant trips.
  • Advances in the navigation instruments (Quadrant, Astrolabe) necessary to solve the problem of determining the longitude with the moving ship, since latitude was much easier to determine.
  • Financing of expeditions, essential for its achievement.


But before continuing, let’s define what an eVTOL is: Electric or Hybrid Vertical Take Off and Landing aircraft. The difference with helicopters is that they claim to be significantly quieter, more accessible (to buy and maintain) and more ecological.


To have a rigorous classification of the different eVTOLs, it is advisable to consult the website of the Vertical Flight Society, which can be visited at the following link:


As I said at the beginning, aircraft need more autonomy and security to be able to perform the missions for which they have been designed. At this time, progress is being made in the storage systems with increasingly larger batteries, but at the moment they do not have sufficient energy density to guarantee long-term flights. To fill this deficiency we have designed a hybrid aircraft that uses the compressed gases of the turbine to move the rotor disk, while with the electric motors two ducted fans (electric motors wrapped in ducts) are propelled that provide the additional thrust to take off and land vertically, being also adjustable for straight and level flight. We are also working on a system with liquid hydrogen and fuel cells, to increase the level of sustainability of the device.


As for safety, our prototype allows self-rotation in case of loss of energy or failure in the propeller system, having an air collection, conduction and compression system (Ram-air) that increases the aerodynamic brake efficiency of the rotor ( para-rotor system) which allows reducing the size of the rotor disk to a very compact and manageable size.


For the navigation system, our multi-year study on navigation systems for remotely piloted aircraft facilitates the development of new, more reliable and robust systems, since during the years in which we were designing and calculating both aircraft and navigation systems , We discovered a new theory of fluid mechanics with which exact solutions are obtained in the problem of bodies submerged in moving fluids. These types of solutions can be applied to aerodynamic and hydrodynamic calculations that can solve many of the engineering problems for which up to now there are approximate numerical methods that give us only an idea of ​​the behavior of the fluids.


The reduced weight of the two aircraft we have designed (Gyrobike and Gyropack) together with their maneuverability, make their utility very indicated in maintenance, inspection, emergency services, and in summary, in any field where a drone can be useful, with the advantage of being able to take a pilot who can perform not only inspections, but also the repairs and maintenance of the monitored infrastructure. It can play a complementary or substitute role for drones, given its low cost of acquisition and maintenance.


And finally, it should be noted that for recreational use and as a single-person aircraft, the development and implementation of this type of aircraft on a green airway network parallel to the existing greenway network, may lead to new business models and market niches for Start up and companies related to the necessary infrastructure and superstructures, such as construction companies, catering and hospitality sector, deployment of telecommunications systems and 5G. In this way, the importance of financing in the development of these aircraft can be greatly favored by the fact that their low manufacturing cost, certification and ease of implementation make interested investors and companies can bet on this new type of solution.

The full paper is available at:

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